Heart valves and cardiac skeleton Flashcards
What is the cardiac skeleton?
Collection of dense, fibrous connective tissue forming four rings in a plane that separates atria and ventricles
What is the purpose of the cardiac skeleton?
Maintains integrity of openings, general structure of heart
Attachment point for valve cusps and cardiac muscles
Serves as an electric isolation of atria and ventricles; no crossed neural pathways
What is the trigone?
the trigone is the fibrocartilage connecting theThe mitral valve ring, tricuspid valve ring, and the aortic valve ring
they are connected in a single unit by the cardiac skeleton
Which valve isn’t connected by the cardiac skeleton?
pulmonary valve
How doe the AV (mitral and tricuspid) valves function?
use a parachute model where the outside edges are held in place by the cardiac skeleton, and the valve leaflets (cusps) are loose
What stops the leaflets of the AV valves from collapsing into the atria?
The leaflets are inhibited from collapsing into the atria by the papillary muscles and chordae tendineae.
What are the position of the AV valves during diastole (ventricular relaxation)?
— the valves open passively as arterial pressure exceeds ventricular pressure.
What are the position of the AV valves during systole (ventricular contraction)?
the valves close due to a relatively greater ventricular pressure, but their closure is limited, and the cusps seal and do not collapse due to the tensile strength of the chordae tendineae and the contraction of the papillary muscles.
What is the function of the semilunar valves (aortic & pulmonary)?
Sinuses in each leaflet catch blood and cause the valve to close when arterial pressure exceeds ventricular pressure; there are no ligaments or muscle associates with this mechanism
What is the shape of the semilunar valves?
The semilunar valves (aortic and pulmonary) are at the root of their respective great vessel; each has three leaflets
What position are the semilunar valves during diastole (ventricular relaxation)?
valves remain closed as increased arterial pressure forces cusps down
What is the position semilunar valves during systole (ventricular contraction)?
: as the relative ventricular pressure increases, the valves open
